1. Field
One embodiment of the present invention relates to an injection molding machine configured to perform in-mold formation.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 10-128787 discloses a mold used for in-mold system. An overlay film is set between the convex die and concave die of the mold in the state where the overlay film is heated and softened. Subsequently, the air is discharged from inside the concave die through small holes communicating between the interior and exterior of the concave die, in such a manner that the film comes into tight contact with the inner surface of the concave die. Molten resin is injected into the mold from the injection port provided in the convex die. When the molten resin is cooled and hardened in the mold, the film is laid over the resin. In this manner, a plastic molded product is completed.
A molding product of in-mold system is sometimes coated with a metallic thin film so that the product has a high-quality appearance. When the metallic film is used, it may be electrostatically charged. If the static electricity is left as it is, it may be discharged when the molding product is pulled out from the mold, causing a current to flow from the molding product to the mold. If this happens, an opening may be formed in the metallic thin film. Although the molding product has to be discharged, this operation is performed by the operator during the molding cycle. Specifically, the operator discharges the metallic thin film by use of a discharge gun or a discharge brush. As a result, the cycle time required for molding is inevitably long, resulting in poor manufacturing efficiency.